1. Field of the Invention
The present invention relates generally to exercise equipment and, more particularly, to a variable resistance treadmill that simulates the resistance of pushing and pulling large objects such as an automobile or a blocking sled.
2. Description of the Related Art
In the related art, there are many designs for treadmills. Treadmills are a popular way that exercise enthusiasts can enjoy a vigorous cardiovascular workout that one would normally get from jogging or running without having to leave the home or gym. Typically, a continuous loop belt made from high strength rubber is supported between two rotating spindles supported by a frame to provide a surface where an exerciser may walk, jog, or run. Many schemes exist where the resistance of the rotating belt is varied according to the users desire to give an optimum workout. Many treadmills now have modern electronics to control the resistance as well as monitoring performance data on the user such as equivalent distance run, speed, time, and even the heart rate of the user. Some treadmills are even motorized to give the user a constant speed workout. However, this significantly reduces the amount of work required by the user to keep the belt turning.
The present invention provides the constant speed workout of a motorized treadmill by utilizing conventional weight lifting plates or other fixed mass placed on the ends of one of the rotating shafts to act as a flywheel. The user can adjust the mass moment of inertia of the belt by selecting plates or other fixed mass of differing weight. A mechanism is placed around the shafts to control the rolling resistance of the belt. Conventional treadmills also are limited in the type of exercise that may be done on them. The present invention also simulates the rolling resistance of objects such as an automobile and pushing/sliding resistance as one would experience in pushing a blocking sled or pulling (sprinting) a sliding weight such as a tractor tire. This gives an exerciser additional workout options not available on conventional treadmills. The present invention is mostly designed from conventional, off-the-shelf materials lending to low cost and ease of construction.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention; however, the following references were considered related:
U.S. Pat. No. Inventor Issue Date 5,595,556 Daleabout et al. January 21, 1997 5,282,776 Daleabout et al. February 1, 1994 5,527,245 Daleabout et al. June 18, 1996 5,318,491 Houston June 7, 1994 5,000,440 Lynch March 19, 1991 4,687,195 Potts August 18, 1987 4,151,988 Nabinger May 1, 1979